Posters

Intrastromal corneal ring segments for keratoconus: major determinants of self-reported vision-related quality of life

Poster Details

First Author: I.Laíns PORTUGAL

Co Author(s):    A. Martins Rosa   P. Ramos   M. Silva   M. Silva   M. Quadrado   J. Murta

Abstract Details

Purpose:

To determine the main postoperative visual and refractive predictors of self-reported vision-related quality of life (QoL) in patients with keratoconus (Kc) submitted to intrastromal corneal ring segments (ICRS) implantation.

Setting:

Department of Ophthalmology, Centro Hospitalar e Universitário de Coimbra, Coimbra, Portugal.

Methods:

Cross-sectional study. At their regular follow-up, patients with Kc submitted to ICRS (Keraring™ Mediphacos, Belo Horizonte, Brazil) implantation with femtosecond laser (IntraLase 60 kHz, IntraLase Corp), minimum follow-up of 6 months and no other ocular co-morbidities, were invited to participate. Only subjects with ICRS in both eyes, or ICRS in one eye and fellow-eye with a best-corrected visual acuity (BCVA) equal or superior to 20/40 were included. Besides the standard ophthalmologic evaluation and corneal topography with Orbscan IIz&trade system (Bausch & Lomb, USA), patients were submitted to aberrometric wavefront evaluation with OPD-SCAN III&trade (NIDEK, USA) and answered the Portuguese version of Visual Function Questionnaire (VFQ-25). VFQ-25 score was calculated according to authors' guidelines and internal consistency reliability was assessed using Cronbach's α. To determine the clinical predictors of VFQ-25, generalized linear estimating equations (GEE), which correct unbiased handling of repeated measures in subjects, were generated. The final chosen model was the one with the best statistical parameters and which maintained the clinical relevance.

Results:

Fifty-three consecutive Kc eyes (42 patients) with median follow-up of 12 months were included. After ICRS implantation, there was a significant improvement of BCVA (p<0.001), spherical equivalent (SE) (p=0.004) and topographic parameters (p≤0.009). The mean postoperative corneal coma was 2.50±1.06µm and mean higher order corneal aberrations (HOA) were 3.51±1.29 µm. Multivariate GEE analysis revealed that VFQ-25 total score was significantly correlated with gender (men more satisfied, β=-43.44, p<0.001), binocular postoperative BCVA (β=-14.48; p=0.027), SE (β=3.19, p<0.001) and corneal coma (β=-11.43, p<0.001). Refractive cylinder was not correlated with better total scores. The model including total HOA revealed similar results (β=-10.40, p=0.010). In the analysis of the VFQ-25 subscales, besides gender, HOA, namely coma, were the most significant predictors.

Conclusions:

Postoperative self-report satisfaction after ICRS implantation in Kc is better in men with low SE and better BCVA. Corneal aberrations, namely coma, seem to be significant predictors of visual-related QoL, even after adjusting for other parameters. ICRS implantation normograms should consider them in order to improve patients' daily visual satisfaction. FINANCIAL INTEREST: NONE